Electrolytes, such as sodium, potassium, calcium, and chloride ions, regulate the human body's nervous system, metabolic processes, renal function, vision, cardiac operation, pH balance, and olfactory senses. The body requires a precise balance of electrolytes in intracellular and extracellular fluids to function properly, and through absorption by the intestines or excretion by the kidneys, the body adjusts electrolyte levels accordingly. Neither the intestines nor the kidneys can function, however, if either the electrolytes are not present to be absorbed or are overabundant and cannot be excreted.
Electrolytes may be depleted by excessive sweating, diarrhea, vomiting, or the use of diuretics, and depletion can lead to seizure, coma, or even death. Children are particularly susceptible to the loss of electrolytes during flu or other illness. An otherwise healthy person can experience greater than normal electrolyte levels during dehydration, which can also occur during a workout or as a result of vomiting and diarrhea. More severe dehydration can lead to a weak pulse, rapid breathing, and disorientation. Furthermore, the body's ability to sweat is diminished if fluids are unavailable. Because sweating is the body's primary cooling mechanism, a dehydrated person can easily overheat, which can cause a range of conditions from cramps to heatstroke.
While commercially available sports drinks and pediatric electrolyte supplements are available to replenish both fluids and electrolytes, an individual simply may not recognize his vulnerability or the rapidity with which electrolytes can be depleted as a result of sickness or during strenuous activity.